As far as I know (but that doesn't mean much), the only file type .xlsx cannot save VBA codes. If you try to save VBA codes with this file type, you get a warning every time. These warnings have apparently been consistently ignored.
Here is some information about self-help
1. Repair a damaged workbook Click on File> Open. Click the location and folder that contains the damaged workbook. In the Open dialog box, select the damaged workbook. Click the arrow next to the Open button, and then click Open and Repair